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Fee Estimation

Bitcoin transaction fees are paid to miners to include your transaction in a block. Getting the fee right is important - too low and your transaction may take a long time to confirm, too high and you waste money.


How Fees Work

Fees are calculated based on the size of your transaction in virtual bytes (vbytes) multiplied by the fee rate in satoshis per vbyte (sat/vB).

The Formula

Fee = Transaction Size (vbytes) × Fee Rate (sat/vB)

A typical single-input, two-output transaction is about 140 vbytes. At 10 sat/vB, the fee would be 1,400 sats.


Fee Estimation Tools

Shows current mempool conditions and recommends fee rates for different confirmation targets. Available on your own node for privacy.

Most wallets estimate fees automatically. Sparrow, Samourai, and others let you set custom fee rates.

Calculate estimated Whirlpool CoinJoin fees. Available at whirlpoolfees.com.


Fee Market

The fee market fluctuates based on demand:

Demand Level Fee Rate Confirmation Time
Low 1-5 sat/vB 1-6 blocks
Medium 5-20 sat/vB 1-3 blocks
High 20-100+ sat/vB 1-2 blocks

Privacy Considerations

Using exact integer sat/vB values (like 10 sat/vB) can be a wallet fingerprint. Some wallets use non-integer values to avoid this.

Replace-By-Fee (RBF) signaling reveals wallet capabilities. Not all wallets support RBF.

Using third-party fee estimation services leaks your transaction details. Use your own node for fee estimation.


Best Practices

  • Use Your Own Node


    For fee estimation, use your own node to avoid leaking transaction details.

  • Avoid Round Fee Rates


    Use non-integer values like 10.3 sat/vB instead of 10 sat/vB.

  • Check Mempool Conditions


    Before sending, check mempool conditions to avoid overpaying.

  • Use RBF When Possible


    RBF allows you to bump fees if your transaction is stuck.

  • Be Patient During Low Fees


    During low-fee periods, you can save money by waiting.